Add common.search_source_by_keys method

server/entertainment_decider/common/__init__.py

@@ -8,6 +8,9 @@ from ._itertools import (
     iter_lookahead,
     limit_iter,
 )
+from ._search import (
+    search_source_by_keys,
+)
 from ._setting_handler import (
     update_bool_value,
 )
@@ -26,6 +29,7 @@ __all__ = [
     "fix_iter",
     "iter_lookahead",
     "limit_iter",
+    "search_source_by_keys",
     "to_just_number",
     "trim",
     "update_bool_value",

server/entertainment_decider/common/_search.py

@@ -0,0 +1,24 @@
+from typing import (
+    Callable,
+    Optional,
+    Sequence,
+    TypeVar,
+)
+
+
+T = TypeVar("T")
+K = TypeVar("K")
+
+
+def search_source_by_keys(
+    source: Callable[[K], Optional[T]],
+    all_keys: Sequence[K],
+) -> Optional[T]:
+    """
+    tries <all_keys> in <source> and returns first result `!= None`, otherwise `None`
+    """
+    for key in all_keys:
+        item = source(key)
+        if item is not None:
+            return item
+    return None